Thermal energy harvesting, also referred to as thermal energy scavenging, is the conversion of heat energy into electrical energy. The heat energy may be derived from any available sources, such as, for example, ambient heat in the atmosphere or waste heat generated by industrial chimneys, engines and the like. The electrical energy harvested from the thermal energy may then be used as a power source for a variety of high power or low power applications. For example, a thermal energy harvesting device may be used to generate usable electrical energy for low power sensor applications in remote locations where electrical energy is not otherwise readily available. The increasing global demand for clean sources of energy has caused increased focus and research in the areas of thermal energy harvesting in order to more efficiently capture potential sources of electrical energy, particularly sources that are otherwise wasted.
Use of a shape memory alloy (SMA) in thermal energy harvesting devices is known to those skilled in the art. Shape memory alloys undergo a phase change at a certain temperature that may be used to covert thermal energy to electrical energy. For example, U.S. Pat. No. 8,104,278 (issued Jan. 31, 2012) discloses a thermal energy harvesting device that utilizes an SMA. This patent discloses a system for and method of harvesting, storing and converting naturally occurring energy using a shape memory alloy. However, known thermal energy harvesting devices utilizing an SMA suffer from various disadvantages, including having complex designs.
Thus, there is a need for an improved thermal energy harvesting device including a shape memory alloy element for generating electrical energy.